Heterovalent Au^III−M^I (M = Cu, Ag, Au) Complexes Derived from Incorporation of [Au(tdt)₂]^- (tdt = Toluene-3,4-dithiolate) with [M₂(dppm)₂]²⁺ (dppm = Bis(diphenylphosphino)methane)

Polynuclear heterovalent AuIII−MI (M = Cu, Ag, Au) cluster complexes [AuIIICuI8(μ-dppm)3(tdt)5]+ (1), [AuIII3AgI8(μ-dppm)4(tdt)8]+ (2), and [AuIIIAuI4(μ-dppm)4(tdt)2]3+ (3) were prepared by reaction of [AuIII(tdt)2]- (tdt = toluene-3,4-dithiolate) with 2 equiv of [MI2(dppm)2]2+ (dppm = bis(diphenylphosphino)methane). Complex 3 originates from incorporation of one [AuIII(tdt)2]- with two [AuI2(dppm)2]2+ components through AuIII−S−AuI linkages. Formation of complexes 1 and 2, however, involves rupture of metal−ligand bonds in the metal components and recombination between the ligands and the metal atoms. The Au(tdt)2 component connects to four MI atoms through AuIII−S−MI linkages in syn and anti conformations in complexes 1 (M = Cu) and 3 (M = Au), respectively, but in both syn and anti conformations in complex 2 (M = Ag). The tdt ligand exhibits five types of bonding modes in complexes 1−3, chelating AuIII or MI atoms as well as bridging AuIII−MI or MI−MI atoms in different orientations. Although complexes 1 and 2 are nonemissive, AuIIIAuI4 complex 3 shows room-temperature luminescence with emission maximum at 555 nm (τem = 3.1 μs) in the solid state and at 570 nm (τem = 1.5 μs) in acetonitrile solution.